Pressurized storage system and method of operating



Oct. 31, 1961 E. E. REED 3,006,149

PRESSURIZED STORAGE SYSTEM AND METHOD OF OPERATING Filed Jan. 3, 1956 3Sheets-Sheet 1 INVENTOR. E.E. REED I F BY MAME, am,

A 7' TORNE VS Oct. 31, 1961 E. E. REED .PRESSURIZED STORAGE SYSTEM ANDMETHOD OF OPERATING Filed Jan. 3, 1956 3 Sheets-Sheet 2 FIG. 2

INVENTOR. E.E. REED A T TORNEVS E. E. REED Oct. 31, 1961 PRESSURIZEDSTORAGE SYSTEM AND METHOD OF OPERATING Filed Jan. 5, 1956 5 Sheets-Sheet3 AQVQ IIWg IN VEN TOR.

E.E. REED A 7' TORNEVS United States Patent 3,006,149 PRESSURIZEDSTORAGE SYSTEM AND METHOD OF OPERATING Edwin E. Reed, Bartlesville,Okla, assignor to Phillips Petroleum Company, a corporation of DelawareFiled Jan. 3, 1956, Ser. No. 556,853 11 Claims. (Cl. 61-.5)

This invention relates to an improved pressurized storage system andmethod of operating same.

Constantly expanding production of liquefied petroleum gas has created adefinite problem in providing suitable storage facilities for thismaterial. Due to the high vapor pressure of liquefied petroleum gas,particularly propane, the cost of storage in surface equipment, such assteel tanks, becomes excessive due to the massive construction requiredto withstand the vapor pressure of the stored material in a safe manner.The problem becomes extremely acute where it is necmsary to store largequantities of such materials during the off-season. In addition to theexpense involved, the use of steel tanks is limited by shortages inproduction.

In order to overcome some of these difliculties, it has been proposed tostore liquefied petroleum gas in porous water bearing formations, inwater-leached caverns in salt formations or in abandoned mines inimpermeable shale or in limestone formations. Further, undergroundconcrete storage tanks and buried sections of pipe, have been used tolimited extent in the storage of liquefied petroleum gas.

In my copending application, Serial No. 348,344, filed April 13, 1953,now Patent No. 2,901,889 entitled Pressurized Storage System, there isdisclosed and claimed an underground storage system for liquefiedpetroleum gas Which is capable of storing extremely large quantities ofthis material at a very small cost. The present invention relates to amethod and means for sealing such a system against product losses duringequipment changes and is an improvement over the invention disclosed andclaimed in my said copending application. The storage system of my saidcopending application and the storage system and method of operatinggiven herein are not limited to the storage of liquefied petroleum gas,but are applicable to the storage of any liquefiable gas such asammonia, carbon dioxide, and the like. (Further, the present inventionis not necessarily limited to underground storage systems and can beemployed where steel tanks are used as the pressurized containers.

There are many methods of removing liquefied gas from a storagecontainer. For example, it is well known that a liquefied gas can beforced from a chamber by introducing compressed gas above the liquid. Inother instances, displacement by a second non-contaminating liquid ofgreater density can be employed. One method, and a more generallypreferred method, for removing a liquefied gas from storage is by meansof a centrifugal pump. The pump is usually contained within thepressurized container and can be one wherein the motor driving the pumpis also submerged, or of the type driven by a rotating shaft attached toa motor outside of the container. It is recognized that such pumps willhave to be pulled from the container from time to time for repair orreplacement. To do this, some means must be provided to prevent the lossof large quantities of vapor from the container. There is disclosed inmy said copending application Serial No. 348,344, mentioned above, anapparatus and method to insure that the container can be tightly sealedduring the time the pump is being operated or being inserted orwithdrawn.

In particular, there is disclosed and claimed in said Serial No.348,344, a spring-operated, normally-closed valve at the bottom of acasing providing communication 3,006,149 Patented Oct. 31, 1961 betweenthe surface of the earth and the caverns. The valve stem of said valveis displaced by the pump body disposed within said casing, and therebythe valve is opened when the pump is lowered into operating position.Accordingly, when the pump body is raised the valve closes, therebysealing the cavern or storage container.

I have found that Water flooding of the casing, in which the pump isnormally disposed, during the removal and reinstallation of the pump isa desirable safety feature. Water flooding of said casing has theadvantages of (1) providing a higher pressure in the casing than in thestorage container, and, (2) a decelerator for the pump should it bedropped while being reinstalled. From a safety standpoint, wheninflammable liquids are stored in the storage container, water floodinghas the advantage of completely removing the inflammable liquid andvapors thereof during the pump withdrawal and reinstallation. However,the use of water flooding in conjunction with the bottom hole valve ofmy above referred to copending application Serial No. 348,344, is notcompletely satisfactory because the valve will open when the head ofwater in the casing exceeds the container pressure and allow water toenter the storage container. I have now developed a two-seated shutolfand check valve which can be employed as a bottom-hole valve and whichelim-' inates the above described difliculty. Said new valve, discussedfurther hereinafter, is one of the subcombinations of the presentinvention.

An object of this invention is to provide an improved pressurizedstorage system and method of operating same. Another object of thisinvention is to provide an improved underground storage system forstoring liquefied gases under pressure. A further object of thisinvention is to provide an underground storage system capable of storingliquefied gases having a high vapor pressure for an extended period witha minimum of operating difiiculties. Still another object of thisinvention is to provide a method for withdrawing and reinstalling a pumpin a pressurized storage container without loss of vapors of theproducts stored therein. A further object of this invention is toprovide an improved shutoff and check valve. Still another object ofthis invention is to provide an improved means for sealing one tubingwithin another tubing. Still other aspects, objects, and advantages ofthe invention will be apparent to those skilled in the art upon readingthis disclosure.

Thus according to the invention, there are provided a method andapparatus for withdrawing a pump from a pressurized container withoutloss of pressure from said container. The container is provided with aconduit extending through a boundary thereof and closably communicatingwith the container. A submersible pump is positioned within the conduitadjacent the region of communication of said conduit with saidcontainer. When it is desired to remove the pump, said pump is moved, asby lowering, to a non-operating position within the conduit.concomitantly with the moving of the pump the conduit is closed off fromthe container. The pressure in the conduit is released and said conduitis filled with an inert liquid, such as water, so as to maintain saidconduit in a closed condition. Thereafter the pump is withdrawn. Afterthe pressure is released from the conduit the contents thereof may bevented off or said contents can be displaced with said inert liquid asthe conduit is filled.

When reinstallation of the pump is desired said pump, suspended from adischarge tubing connected thereto, is run into the conduit to anoperating position therein adjacent the region of communication of saidconduit with said container. Pressure between the conduit and thecontainer is equalized and water is pumped from the conduit. As the headof water in the conduit is decreased the valve will concomitantly openand provide communication between the conduit and the container. Analternative procedure is to lower said pump to a non-operating position,pump the water from the conduit, and then raise the pump to an operatingposition, which raising will concomitantly open the conduit incommunication with the container.

Further according to the invention, there is provided apparatus forcarrying out the method of the invention and attaining the abovementioned objects. The apparatus of the invention includes a combinedshutoff and check valve, means for sealing one tubing within anothertubing, and an improved pressurized storage system.

While water has been given as an example of an inert liquid, otherliquids can be employed. Any liquid which is inert, i.e., non-reactiveunder condition of use with the material being stored, has a specificgravity greater than said stored material, and is substantiallyimmiscible with said stored material, can be used. Non-inflammableliquids are preferred. Water is the presently perferred liquid and isused herein for illustrative purposes.

FIGURE 1 is a vertical elevation, partially in section, of part of anunderground storage system constructed in accordance with thisinvention.

FIGURE 2 is a sectional view, partially in elevation, of a shutoff andcheck valve according to the invention.

FIGURE 3 is another view of the valve shown in FIG- URE 2.

FIGURE 4 is an elevation, partly in section, of the Well head apparatusemployed at the surface of the earth for sealing the underground storagecavern.

FIGURE 5 is a sectional view, partially in elevation, of a slip jointsealing means employed to seal one tubing within another tubing.

FIGURE 6 is a disassembled isometric view of a split bushing which formsa part of the apparatus illustrated in FIGURE 5.

Referring now to the drawings, the invention will be more fullyexplained as employed in connection with the storage of liquefiedpetroleum hydrocarbons such as propane and/or butane. In the drawings,like reference numerals are employed to denote like elements. In FIG-URE 1, there is shown a cavern 10 connected by means of a vertical shaft1 1 to the surface of the ground. Cavern 10 can comprise more than onecavern and said caverns can be connected by suitable tunnels. Saidcaverns can be constructed in a number of different ways as illustratedin the copending application of LP. Meade, Serial No. 314,541, filedOctober 13, 1952. Said shaft 11 extends below the floor of cavern 10 toform a sump or well 12 below the floor of said cavern. A metal liner 13lines the shaft from the surface of the earth to the roof of the cavernand is held firmly in place by means of cement 14. A well head 15 closesliner 13 and seals the contents of the cavern from the atmosphere.Access lines 16 and 17 provide communication through the side of liner13 below the seal point of well head 15. Valves 18 and 19 control saidaccess lines. A first conduit or tubing 20 is suspended from well head15 and extends through cavern 10 into well or sump 12. Surrounding saidtubing 20 is an outer tubing 21 which is attached at its upper and lowerends to said tubing 20 as shown. Said outer tubing 21 contains a seriesof perforations 22 near the bottom end thereof and another series ofperforations 23 near the top end thereof. The lower end of tubing 20 hasa series of perforations 24, below the valve 25, which perforationsextend to a point higher than the perforations 22 in outer pipe 21.Perforations 22, 23, and 24 together with the outer tubing 21 comprisecollectively a pump inlet means which is disclosed and claimed incopending application Serial No. 441,244, filed July 6, 1954, by E. S.Miles and E. W. Porter.

Mounted above well head 15 is a slip joint assembly, denotetd generallyby 26, which provides means for sealing a discharge tubing 27 withinsaid first tubing 20. Said slip joint assembly is described furtherhereinafter. A pump 28 is suspended from tubing 27, which serves as adischarge tubing for said pump, and is disposed within tubing 20 at apoint adjacent the region of communication of said tubing 20 with cavern10. Said pump 28 comprises three main parts, i.e., a lower part ormotor, a protector unit mounted above said motor, and a top unit whichcomprises the pumping unit itself. However, herein and in the claims,the term pump, unless otherwise specified, Will be employed generallytoinclude all three parts of said pump, as well as other suitable pumpswhich can be employed in this service. Submersible pumps of this typeare well known to those skilled in the art. Although not shown, it willbe understood that a cable 29 extends from the motor section of saidpump, within the inner space between tubings 27 and 20, to the surfaceof the earth as shown in FIGURES 4 and 5. Said cable attaches to asource of electric power (not shown) for energizing said motor. Saidcable has been omitted from FIGURE 1 for the sake of clarity.

FIGURES 2 and 3 illustrate one modification of the improved valve of theinvention. As shown in FIGURE 2, said valve is closed at its upper seat.Said valve, denoted generally by 25, comprises a valve body 36 which canbe divided into two parts and sealed as shown at 37. However, it will beunderstood that said valve body can be comprised of one continuous pieceof cylindrical tubing. As shown here, valve body 36 is connected to thelower end of tubing 20* by welding as at 38. Obviously other means suchas threads can be employed in connecting said valve body and saidtubing. Likewise, said valve body 36 can be an extension of tubing 20.Mounted within valve body 36 and secured to the inner wall thereof is afirst or lower valve seat 39. Spaced apart from and also secured to theinner wall of said valve body is a second or upper valve seat 40. Spacedapart from said upper valve seat 40 on the opposite side thereof fromsaid valve seat 39 is a perforated guide member 41 which is secured tothe inner wall of said valve body 36. Disposed within the chamberbetween said valve seats 39 and 40 is a valve head 42. Said Valve headis comprised of a first or upper disc 43 and a second or lower disc 44,separated by a spacer plate 45. Spacer plate 45 is a flat metal dischaving a perforation in the center thereof and is provided with a lip 52extending above the surface on both sides at the outer circumferencethereof- Discs 43 and 44 are fiat metal discs having a perforation inthe center thereof. Each of said discs is provided with an outer bevelededge 51 adapted to cooperate with and seat in the corresponding beveledseating surface in valve seats 39 and 40. Said discs are recessed attheir outer circumference on the side opposite said beveled edge 51 forreceiving O-rings 46 between said beveled edge and said lip 52. SaidO-rings are preferably fabricated froma suitable resilient material suchas an oil-resistant rubber, for example neoprene. Said valve head 42 bybeing provided with the upper and lower discs 43 and 44 is thus adaptedto seat in either valve seat 39 or valve seat 40, The split constructionof the valve head together with the resiliency of O-rings 46 provide avery desirable flexibility in fabrication and operation of the valve andit is not necessary to machine and position the valve seats 39 and 40,with respect to each other, with the accuracy which would otherwise benecessary if valve head 42 were otherwise constructed, as for example aone piece disc. It is to be noted there is a double seal between thebeveled edge seating surfaces of valve seats 39 and 40 and the valvehead 42, i.e., there is a metal to metal seal between beveled edges 51and said beveled edge seating surfaces of valve seats 39 and 40, and arubber to metal seal between O-rings 46 and said seating surfaces. Thussmall pieces of foreign matter in valve seats 39 and 40 will not prevent valve head 42 from effecting a seal.

One end of a valve shaft 47 extends through the per.

in their illustrated assembled positions by means of nut 48 and washer53. The other end of valve shaft 47 extends through valve seat 40, theperforation in guide member 41, and terminates with a combined contactmember and spring guide 48. Coil springs 49 are mounted around valveshaft 47 between contact member 48 and a spring guide 54 mounted onguide member 41. A single coil spring can be employed if desired. Springguides 50 are employed to maintain said springs in proper verticalalignment.

It is a feature of the invention that when springs 49 are compressed,spring guides 50 and 54, together with combined contact member andspring guide 48, will form a solid stack when valve head 42 has moved asuflicient distance to seat in valve seat 39. Valve shaft 47 backs upinto space 55 in combined contact member and spring guide 48. Allcompression loading is thus taken off valve shaft 47 and cannot betransmitted to valve seat 39. For example, in a vertical installation,should the pump be lowered too far or dropped during reinstallation(described further hereinafter) the weight or force will be borne byguide member 41. The advantage of this feature will be readilyappreciated by those skilled in the art.

FIGURE 3 shows the valve head 42 of FIGURE 2 disposed in an openposition between valve seats 39 and 40. Said valve has been opened bylowering pump 28 into contact with contact member 48.

FIGURE 4 illustrates in detail the well head assembly employed to sealthe liner 13, tubing 20, and tubing 27. Liner 13 is connected to wellhead 15 by threaded engagement as shown. If desired, a seal weld can beprovided between said liner 13 and well head 15. Tubing 20 is suspendedwithin well head 15 by means of threaded engagement with hanger 56.Hanger 56 is sealed to well head 15 by means of the O-rings shown orother suitable sealing means. Flange 57 is removably attached to flange58 of well head 15. Said flanges are sealed by means of an O-ringtherebetwcen as shown or other suitable sealing means. Mounted withinand sealed to flange 57 is an outer tubing or casing 59, a flange 60sealed to its other end. Discharge tubing 27 extends upwardly throughtubing 20, casing 59, and is attached by means of a coupling 61 to apipe 62 which extends through flanges 63 and 60. Said pipe 62 isattached as by welding, at its circumference to flange 63 but extendsfreely through flange 60. Inner cylindrical member 64 is sealed to andextends downwardly from flange 63 and surrounds said pipe 62. The lowerend of cylindrical member 64 terminates in shoulder 79 (FIGURE whichbears against the inner wall of casing 59 and is provided with suitablesealing means such as the O-ring shown. Cable 29 extends upwardly withinthe inner space between tubing 27 and tubing 20 and out through stuflingbox 65. While a coupling 61 has been shown as connecting tubing 27 topipe 62 within casing 59, it will be realized by those skilled in theart that if desired tubing 27 could be extended upwardly through flanges60 and 63 as described to take the place of pipe 62 within casing 59 andthe coupling effected above flange 63. However, the use of coupling 61and pipe 62 provides a convenient short length of equipment which ismore conveniently handled. Similarly, pipe 62 could be extended to alower level and connect with tubing 27 in well head or lower. However,it is usually more convenient to make the connection between pipe 62 andtubing 27 within casing 59 as shown.

Flange 66 is attached to the upper end of pipe 62. A suitable flangedvalve 67 is attached to flange 66. A suitable discharge pipe 34 (FIG. 1)is attached to the upper end of valve 67 for conducting liquid pumpedfrom the cavern to any desired point.

FIGURES 5 and 6 illustrate in detail the slip joint assembly which formsone subcombination of the invention. Said slip joint assembly was showngenerally in FIGURE 4. It will be noted that a split bushing or spacer71 is provided between the flanges 60 and 63. Said split bushat theirinterface and when drawn together by means of bolt members 73 and 74form a sealed engagement at said interface. O-rings 75 and 76 provide asealing means between said spacer 71 and the flanges 60 and 63. Theposition of cable 29 is shown clearly in FIGURE 5. It will be noted thatthe metal sheathing has been stripped from said cable at the portionthereof which passes through stulfing box 65. Stulfing box 65 is aconventional packing gland assembly and any type of suitable packing canbe employed therein. A vent 77 controlled by valve 78 extends fromcasing 59 at a point above the highest point of shoulder 79 ofcylindrical member 64. Said vent thus provides means for venting thespace between flange 63 and the lower end 79 of cylindrical member 64before disassembling the apparatus.

It will be understood that all cooperating flanges such as flanges57-58, 60-63, 66 and valve 67, are held together in their assembledpositions by means of suitable bolts and nuts. Said bolts and nuts havenot been ill'ustrated so as to simplify the drawings.

In assembling and operating the apparatus, well head 15 is placed onliner 13 and tubing 20, having outer tubing 21 positioned thereon asdescribed, is lowered through shaft 11 and into well 12. It will beunderstood that the portion of tubing 20 having outer tubing 21 thereonis assembled at the surface prior to lowering in the shaft and theremainder of tubing 20 is lowered section by section until it hasreached the desired position in well 12. Hanger 56 is then installed onthe upper end thereof and the seal is effected between hanger 56 and thewell head 15. It will be understood that valve 25 is attached to thelower end of tubing 20, which valve 25 is normally closed so that oncetubing 20 is inserted and sealed into well head 15 no material can passthrough tubing 20 to the surface or between said tubing and liner 13.Casing 59 having flanges 57 and 60 on the lower and upper endsrespectively is then attached to flange 58 of well head 15. Tubing 27,having pump 28 secured to the lowermost sec tion thereof, is loweredthrough casing 59, section by section, until the approximate properlength has been installed. While the upper end of tubing 27 is stillabove flange 60, pipe 62 which extends through flange 63 but is attachedto said flange 63 at its outer circumference is attached to the upperend of said tubing 27 by means of coupling 61. It will be rememberedthat cylindrical member 64 is also attached to flange 63 and extendsdownwardly from the under side of said flange. The assembled tubing 27,pipe 62, and flange 63 is then lowered until the pump 25 has reached itsapproximate normal operatmg position. At this time, split bushing 71 isinstalled around pipe 62 between flanges 60 and 63 and the pump islowered to its normal operating position. The lowering of said pump toits normal operating position will concomitantly open valve 25 throughthe action of the lower end of pump 28 on contact plate 48 which movesvalve head 42 downward from upper valve seat 40 until said valve head 42is disposed in the chamber between said valve seat 40 and valve seat 39.The system is nw ready to receive the material to be stored therein.Said material can be introduced through lines 16 or 17. Any suitabletype of filling mechanism can be employed at the surface of the earthfor introducing the liquid to be stored into lines 16 or 17.

When it is desired or necessary to remove the pump for service, the vent77 is checked by opening valve 78 and any pressure which may haveaccumulated in the space above seal 79 is vented to the atmosphere.Flange 63 is then raised sufiiciently to permit the removal of splitbushing 71. After removal of said bushing, flange 63 is lowered until itabuts flange 60 which lowering will concomitantly close valve 25 bymoving valve head 42 into contact with lower valve seat 39. The contentsof casing 20 are then vented through lines 30 or 31 to the atmosphere.After venting the contents, said casing 20 is filled with water througheither lines 30 or 31. Thereupon, flange 63 is raised until the coupling61 clears flange 60. Coupling 61 is uncoupled, and pipe 62, flange 63,etc. are moved out of the way, tubing 27 is then raised section bysection until the pump has been completely withdrawn from tubing 20.Alternative to venting the contents of tubing 20 after valve 25 has beenclosed at its lower position, said contents can be displaced by wa' teradmitted through line 31. The entering water will cause the lighterhydrocarbons to be floated upwardly and said lighter hydrocarbons can beremoved through line '30, or if desired, through a higher connection incasing 59 (not shown).

It is to be noted that the hydrostatic head of water in casing 20 holdsthe valve head 42 against lower valve seat 39 thus maintaining saidvalve in a closed position during the time the pump is being withdrawnand is removed from the hole. If by some circumstance the water headshould be lost or the pressure in cavern 10 should exceed saidhydrostatic head of water, then valve head 42 will be forced upwardlyagainst upper valve seat 40 and the valve is still maintained in aclosed position. Thus my invention not only eliminates inflammablevapors from the tubing during the pump removal and reinstallationoperations but it also provides the additional safety feature of thecheck valve, because valve is normally closed at its upper seat and willclose at said upper seat due to the action of spring 49 when the valveis not held open.

When the pump is reinstalled, pump 25, attached to the lower end oftubing '27, is lowered through casing 59 of slip joint assembly 26 untilthe approximate proper length has been installed. Pipe 62, flange 63 andcylindrical member 64 are installed as previously described and theassembly is lowered to the approximate normal operating position of pump25. At this time, the pressure within the cavern 10 and the pressurewithin tubing 20 are equalized by means of lines 16, 3-2 and 31. It willbe remembered that equalization is possible because seal 79 by bearingon casing 59 seals tubing 20. After the pressures have been equalized,split bushing 71 is installed as previously described, the pump islowered to its normal operating position, and the water in casing 20 ispumped out through lines 62, valve 33 and line 34. When the head ofwater in casing 20 becomes less than the pressure in cavern 10 plus theforce of spring 49, valve 25 will open and admit liquid from cavern 10into casing 20. At this point a mixture of water and propane will bedischarged by the pump. Said mixture of water can be discharged throughline 34 to any kind of conventional separating means (not shown) at thesurface of the earth. When effluent from said separating means shows allof the water has been removed the propane stream can then be switched tosurface storage or other means as desired.

An alternate procedure in reinstalling the pump 28 is to lower said pumpto its bottom position after pipe 62, flange 63, and cylindrical member64 have been installed. Said lowering to the bottom position willconcomitantly close valve 25 by moving valve head 42 into contact withlower valve seat 39. All the water in casing 20 is then pumped out. Thepressure in casing 20 and the pressure in cavern 10 are then equalizedas previously described. Flange 63 is then raised sufficiently to permitinsertion of split bushing 71, which raising will concomitantly openvalve 25. Flange 63 is then lowered onto the bushing and pump 28 is nowin its normal operating position.

The invention is not limited to employing a well or sump .12 illustratedin FIGURE 1. If desired, said well or sump can be omitted in which casetubing 2t would only extend to a point near the bottom of cavern 10.Herein and in the claims, unless otherwise specified, the

term bottom region is employed generically to include the bottom regionof cavern 10 and any point within sump 12.

As will be understood by those skilled in the art, various othermodifications of the invention can be made in the light of the foregoingdisclosure and discussion without departing from the spirit or scope ofthe said invention.

I claim:

1. An underground storage system for the storage of liquids underpressure which comprises, in combination: a cavern; a first tubingextending into said cavern and establishing communication between saidcavern and the surface of the earth; a second tubing within said firsttubing; a pump suspended from said second tubing and disposed withinsaid first tubing at the region of communication of said first tubingwith said cavern; a pump-actuated double-seated valve disposed belowsaid pump in the lower end portion of said first tubing, said valvecomprising a valve head disposed between and adapted to seat in eitherof spaced apart upper and lower annular valve seats but being normallyclosed at said upper valve seat and being moved to an open position whena valve stem attached to said valve head and extending through saidupper valve seat is contacted by the pump body when said pump is loweredto an operating position, and being moved to a closed position at saidlower valve seat when said pump is moved to a point below said operatingposition; means forming a seal at the surface of the earth at the pointof entry of said first tubing; means including .a slip joint for sealingsaid second tubing within said first tubing, said slip joint permittinglimited vertical movement of said second tubing and said pump withinsaid first tubing without breaking the seal between said tubings; meansfor introducing fluid to be stored into the cavern; and means foractuating said pump whereby said stored fluid can be removed from saidcavern.

2. A bottom hole shutoff and check valve adapted to be mounted in avertical position in the lower end portion of a first tubing extendingto the bottom region of a bore and actuated by a pump suspended from thelower end of a second tubing disposed within said first tubing when saidpump and said second tubing are lowered into said bore, which comprises:a cylindrical valve body; a lower annular valve seat secured to theinner wall of said body member; an upper annular valve seat secured tosaid inner wall of said valve body at a point spaced apart and abovesaid lower valve seat and forming a chamber within said body member andbetween said valve seats; a perforated guide member secured to the innerwall of said body member at a point above said upper valve seat; asingle valve head disposed in said chamber between said valve seats,said valve head being adapted to seat in either of said valve seats; avalve stem attached at one end to one side of said valve head, the otherend extending through said upper valve seat and the perforation in saidguide member, and terminating in a contact member; and a coil springmounted around said valve stem between said guide member and saidcontact member biasing said valve head to a normally closed position atsaid upper valve seat; said valve stem being adapted to move said valvehead into open position between said seats when said pump is loweredagainst said contact member and into closed position at said lower valveseat when said pump is lowered farther into said bore.

3. Apparatus for removing liquid stored under pressure from anunderground storage cavern, which comprises, in combination: a firsttubing extending into a bottom region of said cavern and establishingcommunication between the surface of the earth and said region of saidcavern; a second tubing suspended within said first tubing; a pumpsuspended from said second tubing and disposed within said first tubingat the region of communication of said first tubing with said cavern;said second tubing also being a discharge conduit for said pump; a

lower annular valve seat secured to the inner wall of said first tubingbelow the normal operating position of said pump; an upper annular valveseat secured to the inner wall of said first tubing above said lowervalve seat and below the normal operating position of said pump; a guidemember secured to the inner wall of said first tubing above said secondvalve seat and below said pump; said guide member having a perforationtherein; a valve head disposed between said valve seats and adapted toseat in either of said valve seats; a valve stem attached at one end tosaid valve head, the other end extending through said second valve seat,the perforation in said guide member and terminating in a contactmember; and a spring mounted around said valve stem between said guidemember and said contact member biasing said valve head to a normallyclosed position at said upper valve seat; said valve stem being adaptedto move said valve into open position between said valve seats when saidpump is lowered into normal operating position and contacts said contactplate, and into closed position at said lower valve seat when said pumpis lowered farther to a position below said operating position.

4. Apparatus according to claim 3 including means for introducing waterinto said first tubing so as to establish a head of water therein tomaintain said valve head in closed position at said lower valve seatwhen said pump is withdrawn from said first tubing.

5. Apparatus for sealing a second tubing within a first tubing so as topermit said second tubing to be moved from a first position to at leastone other predetermined position without breaking the seal between saidtubings, which comprises, in combination: a first flange surrounding andfixed to one end of said first tubing; a second flange surrounding andfixed to said second tubing; a cylindrical member attached to one sideof said second flange, surrounding said second tubing and extending intosaid first tubing between said first tubing and said second tubing;sealing means mounted in the end portion of said cylindrical member awayfrom said second flange and bearing against the inner wall of said firsttubing; a split bushing of predetermined thickness adapted to beinserted between said flanges around said second tubing when saidflanges are parted, said bushing being comprised of two parts theadjoining faces of which are adapted for sealing engagement with eachother and means for securing said parts together; and sealing meansbetween said flanges and said bushing.

6. In a pressurized storage system, in combination: a closed containerfor holding a volatile fluid under pressure; a first tubing passingthrough an upper wall of said container and extending into a bottomregion thereof; means comprising a first head for sealing said containerat the point of entry of said first tubing, said first head alsosupporting said first tubing; a second tubing disposed within said firsttubing; a second head comprising a slip joint mounted on said first headfor supporting said second tubing within said first tubing and forming aseal between said first and said second tubings, said slip jointpermitting limited longitudinal movement of said second tubing withinsaid first tubing; a pump attached to the end of said second tubing anddisposed within said first tubing adjacent the region of itscommunication with the interior of said container, said pump beingmovable with said second tubing; a double-seated valve mounted withinthe lower end portion of said first tubing below the normal operatingposition of said pump; said valve comprising a valve head disposedbetween and adapted to seat in either of spaced apart first and secondannular valve seats but normally biased to closed position at saidsecond valve seat, and a valve stem attached to said valve head andextending through said second seat into the path of said pump so thatsaid valve head is moved to open position between said valve seats whensaid pump is moved into said normal operating position by moving saidsecond tubing a first distance within the distance permitted by saidslip joint, and is moved into closed position at said first valve seatwhen said second tubing is moved a farther distance within the distancepermitted by said slip joint.

7. An underground storage system for the storage of a volatile liquidunder pressure which comprises, in combination: an underground cavern; ashaft extending from the surface of the earth to below the floor of saidcavern to form a well below said floor; a first tubing suspended withinsaid shaft and establishing communication between said well and thesurface of the earth; means comprising a first head for suspending saidfirst tubing, sealing said shaft, and forming a seal between said shaftand said first tubing suspended therein; a second tubing suspendedwithin said first tubing from a second head mounted on said first head;said second head comprising a slip joint and forming a seal between saidfirst and said second tubings, said slip joint permitting limitedvertical movement of said second tubing within said first tubing; a pumpattached to the lower end of said second tubing and disposed within saidfirst tubing adjacent the region of its communication with the interiorof said cavern, said pump being movable with said second tubing; adouble-seated valve mounted Within said first tubing below said pump;said valve comprising a valve head disposed between and adapted to seatin either of spaced apart first and second annular valve seats butnormally biased to closed position at said second valve seat, and avalve stem attached to said valve head and extending through said secondvalve seat into the path of said pump so that said valve head is movedto open position between said valve seats when said pump is moved intonormal operating position by moving said second tubing a first distancewithin the distance permitted by said slip joint and is moved intoclosed position at said first valve seat when said second tubing ismoved a farther distance within the distance permitted by said slipjoint; conduit means in communication with said first head forintroducing liquid to be stored into said cavern; and conduit means incommunication with said second head for introducing an inert liquidhaving a specific gravity greater than, and which is substantiallyimmiscble with, said stored liquid into said first tubing so as tomaintain said valve head in closed position at said first seat.

8. An underground storage system for the storage of a volatile liquidunder pressure, which comprises, in combination: an underground cavern;a shaft extending from the surface of the earth to below the floor ofsaid cavern to form a well below said floor; a first tubing suspendedwithin said shaft and establishing communication between said well andthe surface of the earth; means comprising a first head for suspendingsaid first tubing, sealing said shaft, and forming a seal between saidshaft and said first tubing suspended therein; a second tubing suspendedwithin said first tubing from a second head mounted on said first head;said second head comprising a slip joint and forming a seal between saidfirst and said second tubings, said slip joint permitting limitedvertical movement of said second tubing within said first tubing; a pumpattached to the lower end of said second tubing and disposed Within saidfirst tubing adjacent the region of its communication with the interiorof said cavern, said pump being movable with said second tubing; adoubleseated valve mounted within said first tubing below said pump;said valve comprising: a lower annular valve seat secured to the innerwall of said first tubing; an upper annular valve seat secured to theinner wall of said first tubing at a point spaced apart and above saidlower valve seat and forming a chamber between said valve seats; aperforated guide member secured to the inner Wall of said first tubingat a point above said upper valve seat; a valve head disposed in saidchamber between said valve seats, said valve head being adapted to seatin either of said valve seats; a valve stem attached at one end to saidvalve head, the other end extending through said upper valve seat andthe perforation in said guide member, and terminating in a contactmember; a coil spring mounted around said valve'stem between said guidemember and said contact member biasing said valve head to a normallyclosed position at said upper valve seat; said valve stem extending intothe path of said pump so that said valve head is moved to open positionbetween said valve seats when said pump is moved into normal operatingposition by moving said second tubing a first distance within thedistance permitted by said slip joint, and is moved into closed positionat said lower valve seat when said second tubing is moved a fartherdistance within the distance permitted by said slip joint; conduit meansin communication with said first head for introducing liquid to bestored into said cavern; and conduit means in communication with saidsecond head for introducing an inert liquid having a specific gravitygreater than, and which is substantially immiscible with, said storedliquid into said first tubing so as to maintain said valve head inclosed position at said lower valve seat.

9. The apparatus of claim 8 wherein said coil spring comprises aplurality of coil springs and a spring guide is disposed between each ofsaid coil springs, said spring guides together with said contact memberand another spring guide mounted on said guide member being adapted toform a solid stack upon contact of said contact member by said pump witha force greater than the force necessary to seat said valve head in saidlower valve seat.

10. Apparatus according to claim 7 wherein said second head comprising aslip joint comprises, in combination: a first flange surrounding andfixed to the upper end of a third tubing, said third tubing surroundingsaid second tubing; a second flange surrounding and fixed to said secondtubing; a cylindrical member attached to the lower side of said secondflange, surrounding said second tubing and extending into said thirdtubing between said second tubing and said third tubing; sealing meansmounted in the end portion of said cylindrical member which is disposedaway from said second flange and bearing against the inner wall of saidthird tubing; a split bushing of predetermined thickness adapted to bein serted between said first and second flanges and around said secondtubing when said flanges are parted, said bushing being comprised of twoparts the adjoining bases of which are machined and adapted for sealingengagement with each other and means for securing said parts together;sealing means between said flanges and said bushing; a third flangesurrounding and fixed to the lower end of said third tubing, said thirdflange being adapted to rest on and coast with a fourth flange sealn yengaged to said first tubing and forming a part of said first head; andsealing means between said third and fourth flanges.

11. A shutofi and check valve comprising: a cylindrical valve body; afirst annular valve seat secured to the inner wall of said valve body; asecond annular valve seat secured to said inner wall of said valve bodyat a point spaced apart from said first valve seat and forming a chamberwithin said cylindrical valve body and between said valve seats; a valvehead disposed between said valve seats in said chamber and adapted toseat in either of said valve seats; a guide member secured to the wallof said valve body at a point spaced apart from said second valve seaton the opposite side from said first valve seat,-

said guide member having a perforation therein; a valve stem attached atone end to said valve head, the other end extending through said secondvalve seat, the perforation in said guide member, and terminating in acontact member; a plurality of coil springs mounted around said valvestem between said guide member and said contact member for biasing saidvalve head to a normally closed position at said second valve seat; aplurality of spring guides, each disposed between an adjacent pair ofsaid springs; another spring guide mounted on said guide member; saidvalve stem being adapted to move said valve head into an open positionbetween said valve seats upon application of a force to said contactmember and into a closed position at said first valve seat upon anincrease in said force; and said spring guides, together with saidcontact member, being adapted to for-m a solid stack upon application ofa force to said contact member greater than the force necessary to seatsaid valve head in said first valve seat.

References Cited in the file of this patent UNITED STATES PATENTS1,148,160 Eynou July 27, 1915 1,917,193 Hueber et a1. July 4, 19332,168,591 Tschappat Aug. 8, 1939 2,230,830 Coberly Feb. 4, 19412,469,946 Bremer May 10, 1949 2,486,608 MacDougall Nov. 1, 19492,623,725 Sands Dec. 30, 1952 2,639,169 Jones May 19, 1953 2,643,612Coberly June 30, 1953 2,659,209 Phelps Nov. 17, 1953 2,661,062 EdholmDec. 1, 1953 2,749,714 Hunter June 12, 1956 FOREIGN PATENTS 494,471Belgium Mar. 31, 1950

